CSL crankshaft bearing shell

[Jetcat]

Hello,

Can anybody give me an advice if there are problems on the CSL with the crankshaft bearing shells? (http://www.dict.cc/englisch-deutsch/crankshaft+bearing+shell.html)
Some people in Germany recommend to change them on a regular base if the car makes a lot of trackdays.
On my former M3 E46 SMG from 2002, I got them changed by BMW with a letter from Munich for safety-reasons.
Thanks,

[The Gorilla]

Hi,

S54 Engine in production between
Feb 2001 and June 2003 were all
subjected to the 'Bottom end''
recall.

As your car was 2002 and more than
likely running a 2002 built engine
then it would have been subjected
to the recall.

The issue with the shells was identified
prior to CSL engine [ S54 Short block]
production started, although one or two blocks
could have been used ?

As regards changing shells that's more a type of use
and mileage consideration, if your still making
good oil pressure, then personally I would
leave well alone, unless its some sort of
dedicated Race Car or Track Weapon seeing
high revs for most of its running hours.

Regards,

The Gorilla.

[Jetcat]

Thanks,
As my CSL is from 2003, I remember having read somewhere that BMW recommends to change the shells at about 100.000 km.

[shimmy]

Thanks,
As my CSL is from 2003, I remember having read somewhere that BMW recommends to change the shells at about 100.000 km.

Hmmmmmm, prob a good idea :thumbs:

[Monkey]

I had a set fail recently. Replaced the failed head gasket, and literally on the roadtest afterwards they failed. Number 6 was the worst, just managed to save the crank. They had all started to wear though.

That's the first CSL I have seen with the shells failed to be fair. If you're in any doubt, or just want piece of mind I'd just get them replaced. You can uprate to ARP bolts as well if you like. It's not that expensive a repair either when you put it in perspective. Although it would be fairly pricey at a main dealer I would guess.

[shimmy]

I had a set fail recently. Replaced the failed head gasket, and literally on the roadtest afterwards they failed. Number 6 was the worst, just managed to save the crank. They had all started to wear though.

That's the first CSL I have seen with the shells failed to be fair. If you're in any doubt, or just want piece of mind I'd just get them replaced. You can uprate to ARP bolts as well if you like. It's not that expensive a repair either when you put it in perspective. Although it would be fairly pricey at a main dealer I would guess.

How much would you GUESS shells are to replace?

Mine went at 65k Miles,

[sjb]

So did mine, in fact James is probably talking about my car :-D

[Monkey]

Hmm, 2 sets I know of then!

Shells are roughly £130+vat for the set, same again for ARP bolts ( a little less for the genuine ones), a new gasket and 4 hours labour. Something around £700 all inc from us I think.

Some dealers are doing 10+ labour rates for older cars, so not sure if that's applicable. If full labour rate was charged it would be over £1000 though. A drop in the ocean for you CSL boys;)

This is where the warranty comes into its own again. If you have a compliant dealer you can easily get your moneys worth out of that!

When I say its cheap when you put in in perspective I meant against having to buy a bottom end/donor engine(if you can find one!)

When you hear the bottom end starting to go, I would say you have about 10-20 miles driving before it destroys the crank.

65k Shimmy?! wow, that is incredibly premature. Must have had a hard life...;)

[shimmy]

65k Shimmy?! wow, that is incredibly premature. Must have had a hard life...;)

Second place is first of the losers :)


I'm thinking more about the next change :)

[Pooky]

I think there's a fair number that have had shells go straight away after a head gasket change (might not admit it) so there might be a link to how the engine is pressured and restarted after build?

[shimmy]

I think there's a fair number that have had shells go straight away after a head gasket change (might not admit it) so there might be a link to how the engine is pressured and restarted after build?

Mine was a few months after HG change

[Monkey]

I think there's a fair number that have had shells go straight away after a head gasket change (might not admit it) so there might be a link to how the engine is pressured and restarted after build?


Exactly that. Obviously with pinking there is detonation at the wrong point, which may stress the bearings. Then with the additional compression after a head gasket repair it is enough to finish them off.

[alexk]

How often did the cars with the bearing shells change oil and oil filter ?
Shimmy for example ?

[shimmy]

How often did the cars with the bearing shells change oil and oil filter ?
Shimmy for example ?


My oil is changed every half service interval.

[alexk]

My oil is changed every half service interval.

So 12.000 km ?

[shimmy]

So 12.000 km ?

No, about 5-6000 miles (my service intervals are a bit shorter than that) :smokin:

[Mike R]

No, about 5-6000 miles (my service intervals are a bit shorter than that) :smokin:

That's because you is an aminal (sic) ;).

[0-60Motorsports]

If you're changing your connecting rod bearing shells try VAC coated bearings, or EPIC treated bearings and use ARP studs.

[alexk]

So what is the recommendation ?
How often should the bearings be changed ?

[Bounce]

So what is the recommendation ?
How often should the bearings be changed ?Just change the oil more often lol ;)

[alexk]

Just change the oil more often lol ;)

I change it every 3000km.

[0-60Motorsports]

BE bearings will be releasing their new bearings for the S54 soon. Check out their site for more info. I'll be getting a set.

[cslsuperfan]

So what is the recommendation ?
How often should the bearings be changed ?


Alex

I changed mine @ 66,500 miles and then had the HG checked & compression checked as I'm reliably informed the shell change can bring on HG issues.

[Chad]

Reading through posts,Mines on 66500 now. all ready have shells, head gasket shims bolts etc, ready to go in when I get time, was thinking why not do rings at the same time, Anybody done this? And did they notice much difference in performance worthy of the extra cost of rings ?

[select]

I never heard about an issue with the Headgasket which would warrant a change as early as 60.000miles. Seems a bit excessive to me? :smt017

[GregorFuk]

I read in the Bentley manual that these heads should never be skimmed, probably because in doing so you will raise what is an already high compression ratio. So what I’d really like to know is if people are having their heads skimmed when they voluntarily lift them to do the head gasket?

On the instances I’ve had heads off previous engines they have been warped due to overheating and have always required a skim. If you have seen no ill effects and are just lifting the head to pop a new gasket in then I wonder does this still need doing?

[Monkey]

I never heard about an issue with the Headgasket which would warrant a change as early as 60.000miles. Seems a bit excessive to me? :smt017

The earliest I've changed a failed S54 head gasket was 47000 miles:(

Gregor, the headgasket failure on these engines does not appear to be as a result of excessive temperatures, therefore warping of the head is not an issue, and skimming is not necessary. I always check the head and block with a straight edge and never had an issue (others may have).

These gaskets fail between the cylinders, firstly between the end clyinders 1&2 and 5&6, if left I've seen a couple with it blown between every cylinder!

When the head gaskets fail it's the block that seems to take the hit, it starts to burn away where the hot gases are passing across the failed gasket into the adjoining cylinder.

I've got a CSL here currently with a failed gasket, I'll post up some pictures when I'm replacing it to illustrate what I mean.

And no, the heads most definately should not be skimmed!

[Chad]

The earliest I've changed a failed S54 head gasket was 47000 miles:(

Gregor, the headgasket failure on these engines does not appear to be as a result of excessive temperatures, therefore warping of the head is not an issue, and skimming is not necessary. I always check the head and block with a straight edge and never had an issue (others may have).

These gaskets fail between the cylinders, firstly between the end clyinders 1&2 and 5&6, if left I've seen a couple with it blown between every cylinder!

When the head gaskets fail it's the block that seems to take the hit, it starts to burn away where the hot gases are passing across the failed gasket into the adjoining cylinder.

I've got a CSL here currently with a failed gasket, I'll post up some pictures when I'm replacing it to illustrate what I mean.

And no, the heads most definately should not be skimmed!. Hi monkey what are your thoughts on doing rings at same time as head gasket and shells , really not much more of a job to pop some rings in, regarding restoring lost power on these old motors due to wear, against extra cost of rings, think about £150 a set:bigcry: also has anybody done a recent dyno on a 13 year old csl to see how these old girls are doing..... Ps there's nothing wrong with My motor just a thought as I've already got all parts, bar the rings

[GregorFuk]

. Hi monkey what are your thoughts on doing rings at same time as head gasket and shells , really not much more of a job to pop some rings in, regarding restoring lost power on these old motors due to wear, against extra cost of rings, think about £150 a set:bigcry: also has anybody done a recent dyno on a 13 year old csl to see how these old girls are doing..... Ps there's nothing wrong with My motor just a thought as I've already got all parts, bar the rings

You'd have to hone the bores if you fitted new rings I think. Otherwise they would not bed in and you'd burn oil.

I'd have thought that as long as the engine is showing good compression and the clearnaces are good the engines should be on the money. Might be worth having the injectors cleaned. And I guess if the head is off you could lap the valves.

[Chad]

You'd have to hone the bores if you fitted new rings I think. Otherwise they would not bed in and you'd burn oil.

I'd have thought that as long as the engine is showing good compression and the clearnaces are good the engines should be on the money. Might be worth having the injectors cleaned. And I guess if the head is off you could lap the valves.
Hi,yes have thought about all this, would do valve seals at the same time, probably All a bit over the top on a 65 k mile car , but to be honest I get just as much fun out or ripping it to bits now as driving the Csl , really like it to be at its very best,

[Monkey]

I've honestly never had a reason to replace rings on these. If a cylinder leakage test is carried out and the readings are acceptable there would be nothing to gain from replacing them.

If you want to replace them anyway you would need to measure the bore to see if there is any wear, and whether it is in tolerance or not. If it is you could just go ahead and fit the new rings.

It's a massive job to be honest, and not one that most would want to undertake voluntarily!

Yes if the head is off you could lap the valves in, however I would go back to the cylinder leakage test and if the values are ok again there would be nothing to gain by doing this. These dont suffer from coking up, so generally it's not necessary to clean the ports. When replacing the head gasket the head is not stripped (assuming inspection shows no issues).

With regards to the original post topic (big end shells), I've only personally seen 2 cars fail so it is a small percentage.

[Chad]

Regarding rod Shells, when replacing shells, does BMW have anyway of polishing of debris on crank faces left by worn shells, while in still In motor, possibly a good question for monkey,any info on this mate

[Monkey]

Hi Chad,

We do not have such a tool I'm afraid. If there's any sort of pick up on the crank then it's usually pretty big issue. Depends what you mean by debris!

When replacing bearing shells it's normal procedure to use plasti gauge to measure the clearance. Depending on the results of that will tell you which size crank shells are needed.


Regarding rod Shells, when replacing shells, does BMW have anyway of polishing of debris on crank faces left by worn shells, while in still In motor, possibly a good question for monkey,any info on this mate

[Chad]

Hi Chad,

We do not have such a tool I'm afraid. If there's any sort of pick up on the crank then it's usually pretty big issue. Depends what you mean by debris!

When replacing bearing shells it's normal procedure to use plasti gauge to measure the clearance. Depending on the results of that will tell you which size crank shells are needed.
Ok that sorts that, Not that mine needs doing, just that I have a spare crank that needs a bit of TLC, my local engine specialist recon they can polish spare crank , not a regrind, to be as good as new, it does have some signs of pick up but mics up ok, cheers monkey any thoughts on that are welcome. Chad

[GregorFuk]

Can I ask. When people are replacing shells, cams, followers etc how are they running their engine in?

I have always assumed that the first 1000mile service is such big deal for these engines because they come with a different 'running in oil'. One would assume that if you are changing the aforementioned bits then you need to go through the process again. If that is the case that what oil should be used?

[Bounce]

Was always told the running in oil was a myth and they used TWS

[select]

Can I ask. When people are replacing shells, cams, followers etc how are they running their engine in?


When i had mine done, i specifically asked if i need to run it in. They said no.
Running-in Procedure is not because of the bearing shells but more about the cylinder wall and the pistons.

EDIT: I should add that i only had my bearings replaced, i think if cams have been replaced you should defininately give the engine some time to run it in.
In that case i would just stick to the regular BMW Running in Routine.


Was always told the running in oil was a myth and they used TWS
As far as i know they use some light oil for running in. Something like a 5w-30? Not sure though.

[Chad]

Hi Chad,

We do not have such a tool I'm afraid. If there's any sort of pick up on the crank then it's usually pretty big issue. Depends what you mean by debris!

When replacing bearing shells it's normal procedure to use plasti gauge to measure the clearance. Depending on the results of that will tell you which size crank shells are needed.

Thought I'd add some pictures of striped down spare csl motor as there doesn't seem much about on forum... Back to crank. What the views on pick up on this crank, would you get this polished up or just bang in some new shells , I would imagine this is typical of most cranks. Before reshelling ????

[Chad]

A few vanos Head and cam shaft pics for reference

[Monkey]

Thought I'd add some pictures of striped down spare csl motor as there doesn't seem much about on forum... Back to crank. What the views on pick up on this crank, would you get this polished up or just bang in some new shells , I would imagine this is typical of most cranks. Before reshelling ????

Hi Chad,

Can you feel that pick up with a sharp pick? or your finger nail? If so it would need some attention. You'd also have to measure it with the plastiguage to see if its excessively worn, and to determine which shells you put in when you put it back together.

[Chad]

Hi Chad,

Can you feel that pick up with a sharp pick? or your finger nail? If so it would need some attention. You'd also have to measure it with the plastiguage to see if its excessively worn, and to determine which shells you put in when you put it back together.

Hi James. Yes you can definitely feel some light pickup with finger nail, but doesn't appear to affect measurements, As in photo, interesting thing pickup arrears to be mainly on rod bearing 3 and 4. Also mains bearings either side and centre, appear to take the most abuse. And sprocket side no 1 main bearings is slightly the most warn . Out of interest, a a local engine shop recon this pickup on crank bearings faces should polish up perfectly, out of interest including some photographs , measurements taken and close up photos ..what's your take on measurements, regarding shells! I'm thinking refitting std shells... :thumbs:

[Chad]

Sorry more pictures. This motor and crank spun a shell at about 70 or 80k miles. New shell fitted ran on for another 20k ..but can't remember which one spun .

[Chad]

Imagine of shells. From rod 3 and 4. Definitely more wear to these shells, which coincides with pickup on bearing faces 3 and four, ... Would be interested to hear if this is typical of csl or std m3. Other rod shell don't look to bad, and this coincides with other crank bearing faces being fairly pickup free, ... also noticed most of wear appear to be or the rod shell , bottom shell definitely have less wear in general, ... pictures shows rod 3+4 first. I've definitely seen shell bearings looking a lot worse, so can only imagine once you can see the copper colour on shells there will be a fair amount of pickup on crank faces, pity BMW don't do some kind of temporary shell that can be fitted to polish up crank faces and be then removed......Hopefully of interest to someone

[niall1]

I recently hit 70k miles in mine and as it's no longer my daily I thought it better to have some preventative maintenance with a bottom end rebuild at this service, as I had read about issues with these engines around this mileage. The car has always been regularly serviced and has only done a handful of track days in it's 70,000 miles (almost 50k of those in my care).

The bearings were almost down to the copper! Just a heads up for those still using their cars as they were meant..

Niall

[Chad]

I recently hit 70k miles in mine and as it's no longer my daily I thought it better to have some preventative maintenance with a bottom end rebuild at this service, as I had read about issues with these engines around this mileage. The car has always been regularly serviced and has only done a handful of track days in it's 70,000 miles (almost 50k of those in my care).

The bearings were almost down to the copper! Just a heads up for those still using their cars as they were meant..

Niall
Pictures of the shells in previous post, are of the second set of shells fitted, they only did 30k maximum. These shells are from the first set including spun shells at about 70k :whistle:

[Chad]

Hi Chad,

Can you feel that pick up with a sharp pick? or your finger nail? If so it would need some attention. You'd also have to measure it with the plastiguage to see if its excessively worn, and to determine which shells you put in when you put it back together.

Hi Out of interest, on the 59.75 or 60.00 main shells. what is the difference in size? between yellow , green ,white shells, I take it the white shell has more meat, green in the middle, yellow the least meat..main shell,in .00mm ...... Bmw don’t give this colour option on rod shells just the two sizes 49.00 48.75. ... are the 48.75 shells for reground cranks? Or did bmw do two crank sizes, surely they never wear that much ,,, if the 48.75 are for reground cranks then bmw only do one size for rod shells , unlike mains , ..Tech minded only need reply. Unless you really want to,,, :whistle:

[Chad]

Hi Out of interest, on the 59.75 or 60.00 main shells. what is the difference in size? between yellow , green ,white shells, I take it the white shell has more meat, green in the middle, yellow the least meat..main shell,in .00mm ...... Bmw don’t give this colour option on rod shells just the two sizes 49.00 48.75. ... are the 48.75 shells for reground cranks? Or did bmw do two crank sizes, surely they never wear that much ,,, if the 48.75 are for reground cranks then bmw only do one size for rod shells , unlike mains , ..Tech minded only need reply. Unless you really want to,,, :whistle:

Anybody or I’m I missing something

[Monkey]

Anybody or I’m I missing something

Hi Chad,

You are correct there are only 2 sizes of bearing available for the big ends, and yes there is a standard size and an option for ground cranks.

As for the mains there is a wider selection of bearing sizes avaiable.

As I mentioned previously, I would only recommend using plastiguage to see which bearing shells you need.

[Chad]

Hi Chad,

You are correct there are only 2 sizes of bearing available for the big ends, and yes there is a standard size and an option for ground cranks.

As for the mains there is a wider selection of bearing sizes avaiable.

As I mentioned previously, I would only recommend using plastiguage to see which bearing shells you need.
Thanks James for confirming that regarding rod shells, as for main shells, is there any technical information as regards thickness difference of the yellow, green,and white shells on std shells, I’m assuming they are only different in 0.01. Or 0.03 difference so to speak just to take up a bit of wear on crank bearing faces. ........ Sorry to blast you with this. Also regarding ring sizes shows two different ring options for std rings, 0 and 00. I’m presuming 00 are to be used on a higher mile engine , any tech info on this appreciated ? £40 price difference also between the two different part numbers I understand measuring end gap etc. ..... Any specific end gap for csl.. thanks for your input James. ,,, speaking to my local engineer suppliers today, they say they would use the 00 term / measurements, to indicate a higher degree of machined /measured accuracy. Phil

[Chad]

Hi Chad,

You are correct there are only 2 sizes of bearing available for the big ends, and yes there is a standard size and an option for ground cranks.

As for the mains there is a wider selection of bearing sizes avaiable.

As I mentioned previously, I would only recommend using plastiguage to see which bearing shells you need.

When I’ve measured crank bearing face they come out as in photo, so std crank. Very minimal wear on this 100k crank , would have been ideal if bmw give you the option of shells as they do on main shells, especially for no 3 . :thumbs:

[Chad]

When I’ve measured crank bearing face they come out as in photo, so std crank. Very minimal wear on this 100k crank , would have been ideal if bmw give you the option of shells as they do on main shells, especially for no 3 . :thumbs:

I’ve taken picture from internet,,, What’s the recommend ideal measurement outcome for csl shells ??? I’ estimate I will see .05 plastagauge on rod no 3 shell from what I’ve measured with micrometer, tighter on others. Possibly down to .02 mm

[Chad]

Hi Chad,

You are correct there are only 2 sizes of bearing available for the big ends, and yes there is a standard size and an option for ground cranks.

As for the mains there is a wider selection of bearing sizes avaiable.

As I mentioned previously, I would only recommend using plastiguage to see which bearing shells you need.

Hi James , top marks to you mate going to the trouble of checking with plastiguage, I’m sure 99percent wouldn’t.. I’ve today been round all local autos spares, not one of them even heard of it , never mind what it’s used for.... Having established I’ve got stock crank and only the one shell available, still what is the ideal measurements outcome we are looking for , regarding plastiguage on these bmw crank to bearing face measurements, Eg 0.03 0.02 mm, Do bmw have a recommendation. ???.... sort of irrelevant I know as only one shell available , Any input also welcomed anybody :thumbs:

[Chad]

Found this on internet, bit more information , but no dimensions. Definitely plastiguage will be used to work out best one to use on mains , but could do with actual tolerance required.? Eg if the white shell has more meat on its bones,(so to speak) I’d possibly use this on Number 1 main. As this has the most wear, as this crank used green shells from new . All depending on what bmw recommed shell to crank tolerance....If anybody knows ?

[Chad]

Think this is what I need.

[Chad]

Eventually got some plastiguage from manufacturers, pictures couple of main crank journals , and the two most abused rod journals, shows a basic ball park measurements of bearings wear /conditions .. to compare against bmw bearings chart in previous post. . My measurements with basic micrometer shows a slight difference to bmw spec , Will recheck with a better mic Just to check crank spec again. These are the worn bearings. So new should but them back to spec. :thumbs: Number one main crank shell seems to pull the most wear , about 0.055 mm possibly as it pulls timingchain / oil pump, .... Conrod bearing clearance. Should be between 0.030. And 0.070 mm on spec sheet,Below 0.030 is to tight bmw recommendation would be to fit another set of new shells .(... Update... ) bmw now, say min 0.040 shell bearing clearance, After that new Conrods

[Chad]

If off interest to anybody rod Journal bearing spec and shell clearance. ........NOW from what I’ve read bmw have changed from min 0.03. To min 0.04. Retrospectively. (I’d work to 0.04 ).

[Chad]

Thanks James for confirming that regarding rod shells, as for main shells, is there any technical information as regards thickness difference of the yellow, green,and white shells on std shells, I’m assuming they are only different in 0.01. Or 0.03 difference so to speak just to take up a bit of wear on crank bearing faces. ........ Sorry to blast you with this. Also regarding ring sizes shows two different ring options for std rings, 0 and 00. I’m presuming 00 are to be used on a higher mile engine , any tech info on this appreciated ? £40 price difference also between the two different part numbers I understand measuring end gap etc. ..... Any specific end gap for csl.. thanks for your input James. ,,, speaking to my local engineer suppliers today, they say they would use the 00 term / measurements, to indicate a higher degree of machined /measured accuracy. Phil ..found ring clearance, if anybody needs to know, also main bearings shell Difference....as for ring sizes bmw shows three sizes, 0 and 00 And +0.20 From what I’ve found I think it is the bore size, as on engine block spec picture bellow, So I’m guessing not all blocks are the same, and need to be checked when ordering pistons and rings , unless anybody knows differently, ??? Possibly+0.20 is first oversized,

[Chad]

Hi Chad,

You are correct there are only 2 sizes of bearing available for the big ends, and yes there is a standard size and an option for ground cranks.

As for the mains there is a wider selection of bearing sizes avaiable.

As I mentioned previously, I would only recommend using plastiguage to see which bearing shells you need.. Just to add to the post regarding mains shells , and colour coded shells. :banghead:

[Mike R]

Superb reference information :thumbs: :beer:

[Chad]

Sorry chaps but nothing better to do . So thought I’d put a comparison of new shells i have , , “”mains”” Black shell king race, silver oem yellow code shells mains inc thrust bearings, note different elongated hole in king shells. Also picture of rod shells black kings. Silver bmw, with weight of rod bearings. Will do weights of mains later. These king bearings do look to have good surface finish and look like a good quality finish.... “” Anybody have experience of the king race””.

[select]

Thanks for all the informations chad. Very interesting. Unfortunately i have nothing to say about the King race shells. But why did you choose them over OEM?

[Chad]

Thanks for all the informations chad. Very interesting. Unfortunately i have nothing to say about the King race shells. But why did you choose them over OEM?
Hi select. I’ve got both sets. Rod and mains. Both oem and king, haven’t decided 100 percent. Wanted to compare two completely different types, But will probably go with king on this 100k engine, but put oem in my car motor when I decide to do that engine,, price wise king’s are a lot cheaper than oem, suppliers tell me that kings would stand up better on a engine that is used more eg race engine that is kept more on higher revs for longer, But I’ve no real proof other than suppliers say so, They also claim even if shell spun wouldn’t damage crank, but personally not sure on that claim :whistle: As I’ve mentioned this is a project build to see how things turn out. So all feedback is welcome good or bad :thumbs:

[select]

Fair point regarding the price difference. Unfortunately i am no engine builder so i can not add anything of value. But one thing to consider is that this engine has worked for 100k miles so they have proved their worth more or less ;)

With these new shells you are adding a unknown variable and if it goes bust it will be very difficult to prove that it was because of the shells. But if they are of better quality while being cheaper than OEM its certainly a tough choice to make.

[Chad]

Fair point regarding the price difference. Unfortunately i am no engine builder so i can not add anything of value. But one thing to consider is that this engine has worked for 100k miles so they have proved their worth more or less ;)

With these new shells you are adding a unknown variable and if it goes bust it will be very difficult to prove that it was because of the shells. But if they are of better quality while being cheaper than OEM its certainly a tough choice to make.
Hi Julian. Fair enough point regarding oem std shells. This motor had already spun a shell some 20or 30 k ago , new shells oem were fitted by a bmw tec. Good lad to,””no names””. as he did it at his home ,, it ran reasonably well up to 100k ,, though they was some of the old shell left on the crank.as crank was never taken out and any kind of polish,,,Later shells didn’t look to bad to be honest, so don’t think pickup on crank was from new shells, original shells were down to copper colour,, I’ve now polished up crank myself old style bootlace job 1000 grade wet dry and metal polish,, all still measured up ok bmw spec, looks prity good. From what I’ve vied So called professionaly polishing isn’t exactly high tech machining “Unless bmw factory done imo”. To be fair can’t really fault oem shells. But they can be suspect and fail to :whistle: Hence request for feedback king shells or other , :thumbs:

[GregorFuk]

They also claim even if shell spun wouldn’t damage crank, but personally not sure on that claim :whistle:

Agreed, that's a strong claim. Did they also offer you a bag of magic beans?

[Chad]

Agreed, that's a strong claim. Did they also offer you a bag of magic beans? magic Beans would take it to over 400 hp. :thumbs:

[Chad]

Bit more info if anybody interested,